Freedman SB (2006) Oral ondansetron for gastroenteritis in a pediatric emergency department. N Engl J Med 354: 1698–1705

Despite recommendations, oral rehydration therapy is underused in children who present to the emergency department with mild-to-moderate dehydration caused by gastroenteritis. In part, such underuse results from the view held by many pediatricians that vomiting is a contraindication for oral rehydration. Freedman and colleagues have, therefore, carried out a double-blind, placebo-controlled trial to determine the efficacy and safety of a single oral dose of the antiemetic ondansetron, with the aim of improving the success of oral rehydration therapy.

In total, 215 dehydrated children, who presented to an emergency department with gastroenteritis, were randomly allocated to receive either a single dose of orally disintegrating ondansetron or placebo. Intense oral rehydration therapy was initiated 15 mins afterwards.

Children who were given ondansetron were less likely to vomit and had fewer vomiting episodes during oral rehydration therapy than those who were given placebo. Those given ondansetron also had a greater oral intake of rehydration fluid and were less likely to require intravenous rehydration than those given placebo. No serious adverse events were experienced by any of the participants. The length of stay in the emergency department was markedly shorter for those in the ondansetron group; however, the rates of hospital admission were similar between the two groups.

The authors conclude that a single oral dose of ondansetron is safe, and is effective for use in the emergency-room setting for children with dehydration caused by gastroenteritis. They note that, by facilitating oral rehydration, ondansetron reduces the need for intravenous rehydration.